Knee joints, which connect the tibia and the femur, are effected through a layer of cartilage, the meniscus, which has a very low friction coefficient but is sensitive to local pressure concentrations. The meniscus is subjected, in use, to compressive and sliding forces. The failure mode of the knee joint is usually wear of the meniscus due to sliding under high-contact forces and/or cracking of the cartilage caused mainly by local pressure concentrations while sliding. Injury and disease can lead to the need to remove the entire meniscus, or portions thereof.
The prior art has suggested a variety of constructions for cartilage replacement in the knee joint. U.S. Pat. No. 5,358,525 discloses a prosthesis consisting of a pad of pliable and compliant shock absorbing material supporting a plurality of small ball bearings which are capable of shifting positions within the interior of the replacement pad as varying loads are applied. U.S. Pat. No. 4,502,161 discloses a meniscus prosthetic comprising a resilient material such as silicone rubber or Teflon reinforced with a mesh of stainless steel or nylon strands.
These and other meniscus prosthetics have not experienced wide adoption in knee joint repair, and most knee joint repairs involve complete removal of the joint and replacement with an artificial joint formed between two bone replacement sections which are adapted to merge with the natural bone remaining after the joint removal.